Environmentalists are invariably "extremists," akin to "yesterday's communists." California's senior senator, Democrat Dianne Feinstein, is sometimes a "liar" and her staff members are "radicals." Bay Area lawmakers want to "turn the Central Valley into a desert."

Looking in the mirror, the 36-year-old Visalia Republican sees a congressman standing up for his constituents.

"I decided a couple of years ago that there was no dealing with the radical environmentalists, because they have such control over the (Democratic) politicians," Nunes said, when explaining his tactics. "The only thing they understand is pain."

Undeniably, Nunes has showcased the San Joaquin Valley's water shortage and its economic consequences. He has forced heated if inconclusive congressional debates. He persuaded Sean Hannity of Fox News to spotlight the region's water crisis. His rhetoric seems to have spurred on Valley colleagues to become more vocal.

"He has absolutely grabbed the issue by throat," enthused Rep. John Campbell, R-Newport Beach. "He has created awareness on a national scale, and without that, nothing happens."

One example: On Thursday, 23 House Democrats defied their own leadership on an unsuccessful parliamentary maneuver designed to underscore unhappiness over San Joaquin Valley water shortages. Nunes was at the forefront of that protest.

But as Nunes nears the end of his seventh year in the House of Representatives, his political aggression is also costing him potential allies. He has antagonized some fellow Republicans. He has provoked revenge from Democratic leaders. At times, he has cracked the traditional bipartisan accord preferred by San Joaquin Valley representatives.

"I have heard from some members, even from those outside the Valley, that in many ways he's making it harder to get things done because of his partisan attitude," said Manuel Cunha, president of the Fresno-based Nisei Farmers League.

Democratic Sen. Dianne Feinstein was more blunt.

"I've been very disappointed in his approach, to hit and hit," Feinstein said in an interview. "I just see him as striking out blindly, and that's really not helpful."

Most broadly, Nunes' approach toward California water policy raises important questions about congressional tactics, strategy and personality. In brief: When is compromise weakness, and when is it victory? Put another way: When is sending a message on a losing vote no longer sufficient, and what happens then?

"He's done an excellent job at raising awareness," Rep. Doc Hastings, R-Wash., said of Nunes. "People are now aware of these things."

Or, as Nunes put it: "If I come across as angry, it's because I am."

That's sometimes obvious, as in an Oct. 14 hearing of the House Rules Committee. The panel chairwoman, 80-year-old Rep. Louise Slaughter of New York -- herself a stout Democratic partisan -- physically recoiled when Nunes harshly denounced the committee's unwillingness to allow California water amendments.

The amendments themselves, such as one suspending the Endangered Species Act, are opposed by the Obama administration. Their primary purpose, some on Capitol Hill believe, is to send a political message.

Payback can take several forms. Campbell, for one, had his resolution honoring the University of California at Irvine men's volleyball team blocked by Democratic leaders because he sided with Nunes on a water vote. Nunes himself has been left out of certain water policy discussions. He doesn't request earmarked spending, though, so that can't be taken away from him.

"Devin has been both effective and deleterious," said Rules Committee member Rep. Dennis Cardoza, D-Merced. "It's totally appropriate to try to fix this (water) problem, but I've been disappointed with him on some of his tactics."

Nunes' reputation is such that politicians sometimes see his hand even when Nunes himself denies involvement.

When some Republicans recently mulled a primary challenge to Rep. George Radanovich, R-Mariposa, experienced politicos speculated that Nunes was involved. Nunes and Radanovich have had strained relations at times, though Radanovich now says they get along fine. Likewise, when farmers booed Rep. Jim Costa, D-Fresno, on Hannity's recent taping of a show, rumors spread that Nunes was covertly responsible.

"That's utter nonsense," Nunes chief of staff Johnny Amaral said when asked about his boss's alleged involvement in either episode.

Nunes, too, said the rumors were unfounded. He was, though, behind a recent Senate confrontation that alienated Feinstein.

In late September, Cunha said, Nunes urgently sought the Nisei Farmers League's support for an amendment to be offered by Republican Sen. Jim DeMint of South Carolina. Nunes was the amendment's original author in the House.

Cunha said he "had the understanding" that Nunes, DeMint and Democratic Sen. Dianne Feinstein were all communicating about the amendment, billed as a way to increase irrigation pumping. Accordingly, Cunha said, he endorsed DeMint's efforts -- which rattled Feinstein, who accused DeMint and his supporters of plotting a legislative ambush. The amendment failed, Feinstein was furious and Cunha felt singed.

"It was wrong on Devin's part," Cunha now says. "He should have reached out to Senator Feinstein; that would have been the right way to do it."

Nunes retorted heatedly that Feinstein was a "liar" for saying she was ambushed. Nunes says DeMint provided Feinstein with several hours advance notice before offering his amendment. More broadly, Nunes denounced both Feinstein and Democratic Sen. Barbara Boxer for accepting the diversion of water for environmental protection.

"Are they representing the views of the radicals? " Nunes asked. "The answer is obviously yes."

A similar legislative hand grenade was tossed on the Senate floor in late July. The Senate was considering a routine measure aimed at easing California water transfers. No one opposed the non-controversial bill. But unexpectedly, citing San Joaquin River provisions of potential concern to Nunes, Republican Sen. Tom Coburn of Oklahoma put a hold on the bill. Feinstein and Boxer had to spend the day wrestling the bill back from Coburn's grasp.

The day-long maneuvering was resolved and had no lasting impact; except, in provoking yet another round of questions of what Devin Nunes is up to.